Interlocking modular tubular pallet

ABSTRACT

The invention pertains to the design of polymer or molded part that can be used for pallets or decking material. A pallet having a plurality of pallet sections each composed of interlocking tubular elements defined by top and bottom surfaces. The interlocking find overlapping sections provide a continuous surface in immovable assembly. The edge of the top surface of one tubular section has a flange that protrudes from it that fits in a corresponding groove of an adjacent tubular section so as to provide a flat connected surface. At least two tubular elements are located next to one another with collinear edges and are oriented in the same direction to support loads on top and bottom surfaces and resist bending. The modular design of the tubular sections allows for the continuous structure to be divided into several regions for ease of repair or serviceability.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates generally to pallets on which articles are stacked or assembled to enable handling and shipment of the articles at minimal handling costs. More specifically, the present invention relates to pallets that can be assembled in modular fashion in several configurations to provide continuous top and bottom surfaces. Even more specifically, the present invention concerns modular sections that can be easily disassembled and reassembled as needed for maintenance.

[0003] The invention relates generally to decking produced from plastic lumber materials. More specifically, the present invention relates to decking that can be assembled in modular fashion with minimum mechanical fasteners in several configurations to provide continuous top and bottom surfaces. Even more specifically, the present invention concerns modular sections that can be easily disassembled and reassembled as needed for maintenance.

[0004] 2. Description of Related Art

[0005] Prior patents in the area of pallets and decking offer sections that do not interlock from the top, require fasteners to connect structures, may not have a continuous surface on top or bottom, and may not be hollow but have a solid thickness. Current designs use materials for pallets and decks utilize adhesives or fasteners to build structure. Historically, pallets and decking are constructed with wood materials, having a plurality of parallel stringers on which are nailed or otherwise secured one or more structural members defining a platform. Pallets and decking have been constructed of extruded or formed metal such as steel or aluminum. Pallets and decking have also been constructed of molded or extruded plastic materials, including virgin plastic material or plastic material that has been recycled or reclaimed from waste. The materials used in said pallets and said decking are connected with mechanical fasteners or bonding agents. Pallets that are constructed of plastic, wood, or metal materials have problems that the present invention addresses. For decking applications, the existing solid plastic lumber is heavier than the conventional wood deck and requires nails, fasteners, or adhesives to hold it together. My invention would reduce the number of fasteners required because the leading edge of one pallet section locks into a groove on the neighboring pallet section from the top. Most pallet designs do not have interlocking sections and as such require fasteners. One patent has interlocking pallet sections, but from the side walls and not the top and bottom walls as in my invention. This side-wall connecting pallet requires fasteners and/or adhesives to hold the structure together. The side-connecting plane results in a shearing plane being formed when weight is added to the top surface. The weight in loaded on the top surface, which is perpendicular to the side-interlocking surface. This is the cause of the shearing plane. The shearing plane is on the side walls and will result in the side walls separating as the weight on the top surface causes the pallet to bend. The side walls must be attached via mechanical fasteners and/or bonding agents. My invention has the interlock connections in the same plane as the weight on the top surface and thus will further engage the interlock connection. Fasteners are not required in my invention nor are bonding agents. The lack of permanent fasteners further illustrates a unique feature of my invention. My inventions is modular and can be easily disassembled and reassembled to connect other tubular sections, if a repair is required.

[0006] Current designs for pallets utilizes fasteners to build structure into the pallet. The U.S. Air Force uses a balsa-wood pallet with aluminum skin to transport cargo in the cargo planes. The aluminum skin is attached to the balsa wood core material with adhesives and rivets. This design causes the pallet to be heavy and also requires the pallet to be repaired at the manufacturing facility in Minnesota. My invention can replace balsa wood core pallet with modular sections that can be attached to the aluminum with rivets. The modular pallet can be repaired in a snap-fit fashion at the location of the cargo facility. A pallet produced with my invention would be lighter, less expensive, and easier to repair than the current balsa wood pallet. For wood decking applications, the wood and most plastic lumber materials are solid and are attached with nails into cross beams. My invention would require fewer nails due to the snap fit design and would be made up of hollow sections. Since most of the bending stresses in a decking application occur on the top and bottom surfaces, material is not needed in the center of the decking section. My invention should result in a decking product that is lighter, less expensive, and easier to install than current solid plastic lumber and lighter, less expensive, and similar in cost to wood products.

SUMMARY OF THE INVENTION

[0007] A tubular structure that snap fit together is provided. The interlocking structure is built based upon a modular structure with overlapping annular sections. One unique and novel aspect is that the structure has continuous surfaces, top and bottom, without any gaps, and has air spaces inside the structure based upon an annular profile section. Also, the structure is unique and novel in that it is made of sections that are interlocking and overlapping and snap together without fastening devices. A pallet produced from the tubular sections would be lighter, less expensive, and easier to repair than current aircraft pallets made from balsa wood and aluminum skins.

[0008] My invention in novel because it is constructed of interlocking modular units, such that the pallet or deck or other structure can be repaired less expensively and much easier than a single unit type of construction. If several modular sections are combined to make a structure, then if one section is damaged, it can be replaced by disconnecting the one bad section from the whole unit and replacing the bad section with a good section. It is novel because it has air sections or tubes inside such that it is lighter than most conventional pallet and decking or related structures that have continuous material throughout the thickness. It is also novel because the invention allows for a continuous planar surface due to the interlocking features of the structure and would allow the ability for one to drive over the structure with a wheeled vehicle, or not allow items on the pallet to fall through the structure and spill on the floor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the preferred embodiment thereof which is illustrated in the appended drawings, which drawings are incorporated as a part hereof.

[0010] It is to be noted however, that the appended drawings illustrate only a typical embodiment of this invention and are therefore not to be considered limiting of its scope, for the invention may be admit to other equally effective embodiments.

[0011] In the Drawings:

[0012]FIG. 1 is an isometric illustration of an assembled structure with six modular sections (1, 2, 3, 4, 5 and 6), end pieces, middle connecting pieces, and cross piece that is constructed in accordance with principles of the present invention;

[0013]FIG. 2 is a fragmentary cross sectional view of the pallet construction showing an extruded single tube with three open channels and showing the interlocking tubular section;

[0014]FIG. 3 is a fragmentary isometric illustration similar to that of FIG. 2 and showing an extruded single tube with three open channels;

[0015]FIG. 4 is a fragmentary sectional view taken along section A-A as depicted in FIGS. 1 and 5 showing the interlocking features of the sections and the use of interconnecting cross piece;

[0016]FIG. 5 is a fragmentary sectional view taken along section B-B as depicted in FIG. 1 and showing the interlocking tubular sections.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0017] Referring now to the drawings and to FIG. 1, a pallet is constructed in accordance with the principles of the present invention and representing the preferred embodiment is illustrated generally at 100. The pallet structure is shown composed of six tubular pallet sections or sections 1, 2, 3, 4, 5, and 6, which are interconnected and which define a pallet structure of integral construction. The interlocking structure is build based upon a modular structure with overlapping annular sections. The annular sections, FIGS. 2 and 3, can be made from metal processing methods, such as extrusion, stamping, machining, welding, etc. The annular sections, FIGS. 2 and 3, can be made from conventional plastic and polymer processing methods, such as extrusion, injection molding, reaction injection molding, resin transfer molding, compression molding, pultrusion, hand lay-up methods, and polymer foaming operations. Other polymer materials that incorporate the design include all thermoplastic and thermoset polymers, rubber polymers, foam polymers, wood filled polymers, organic and inorganic filled polymers organic and inorganic reinforced polymers, wood and metal materials, and other moldable and formable materials. Variations on the manufacturing method include all common thermoplastic and thermoset manufacturing processes, including, extrusion, injection molding, compression molding, Reaction Injection Molding (RIM), thermoforming, rotational molding, Resin Transfer Molding (RTM). The extruded annular section is extruded to the desired length. The extruded sections are then snapped together to form modular sections, e.g., sections 1, 2, 3, 4, 5, and 6, as shown in FIG. 1. The cross section can include one, two, three, or more hollow sections as determined by the forming die. Although six pallet tubes or sections are shown, such is not intended to limit the spirit and scope of the present invention because any suitable number of interconnected tubes or sections may be utilized. Also, elements or sections in the form of structures other than tubular elements or sections may be also within the spirit and scope of the present invention. It is only necessary that the sections that are assembled to form a pallet structure integrity to support objects or articles of predetermined maximum weight and that the pallet be capable of being supported in a floor surface and that the pallet present a substantially planar upper surface on which articles may be stacked.

[0018] As shown in FIG. 1, an example of a pallet structure utilizing the present invention can have six tubular sections that have a interlocking tubular section as described but not limited to FIG. 2 and FIG. 3 and are connected with pallet cross pieces as shown in FIG. 4. The pallet cross piece 600 connects the edges of two joining pallet sections that have a flange on one side and a groove on the opposite side as shown in but not limited to FIGS. 2 and 3. The interlocking tubular sections, e.g., sections 1, 2, 3, 4, 5, and 6 in FIG. 1, may also be connected on the annular end with middle connecting piece 300 and 400 as shown in FIG. 1. Also, the interlocking tubular sections, e.g., sections 1, 2, 3, 4, 5, and 6 in FIG. 1, may have end pieces 200 and 500 in FIG. 1 to close off the annular end of the tubular section and give the appearance of a solid section. A pallet, in FIG. 2, having a plurality of pallet sections having interlocking tubular elements defined by top 20 and bottom 30 surfaces of the pallet sections, as shown in FIG. 3. The interlocking and overlapping sections provide a continuous surface. The interlocking flange design allows for structural integrity, smooth rolling surface on top and bottom. At least two tubular elements are located next to one another with collinear edges and are oriented in the same direction to support loads on top and bottom surfaces and resist bending. The pallet sections 1, 2, 3, 4, 5, and 6 are of generally tubular configuration with planar upper wall 10 defining an upwardly facing planar surface 20 and with a planar lower wall 12 defining a downwardly planar Surface 30 is substantially coplanar with the upper wall of the neighboring tubular section with the same geometry and planar upper wall 14 defining an upwardly facing planar surface 20 and with a planar lower wall 16 defining a downwardly planar surface 30. The edge of the top surface 10 of one tubular section has a flange 11 that protrudes from it and is of such a design that it fits in a corresponding groove 15 of an adjacent tubular section so as to provide a flat connected surface. The top walls 20 and 30 define flange and tab interlocking connectors for securing the pallet sections in immovable assembly. The protruding flanges 11 and 13 are on the top and bottom walls and on the right side with corresponding grooves 15 and 17 on the top and bottom walls and on the left side of the tubular section. The flange can as well be on the left side top and bottom walls with the corresponding groove on the right side top and bottom walls. Some tubular sections can have flanges on both top and bottom walls for the left and right sides. Some tubular sections can have grooves on both top and bottom walls for the left and right sides. Any combination of the flange and groove as fore mentioned to provide interlocking modular sections. Section 1 in FIG. 1 has a configuration with the flanges on the right side of the section and with grooves on the left side of the section. Section 4 in FIG. 1 has flanges on the left side of the section and grooves on the right side of the section. When the two sections come together at the center of the pallet, the sections cannot connect since both sections will have grooves butting together. As shown in FIG. 4, a pallet cross piece 600 connects the two groove sections since it has two flange regions on the left and right sides. It does not have a groove section as shown in fragmentary section view of FIG. 3, which shows interlocking geometry of rectangular cross-sectional configuration being employed to establish interlocking between pallet sections. The pallet sections interlock in a similar way as the flanges 52, 54, 56, 58 from the pallet cross piece lock in the grooves of the pallet sections 62, 64, 66, and 68. In FIG. 4, the illustration depicts a left-handed flange with three hollow sections 700, a right-handed flange with three hollow sections 800, and a pallet cross piece 600. The right-handed flange with three hollow section profile 800 is repeated with similar sections many times to the right until section 1 is built. Similarly, the left-handed flange with three hollow section profile 700 is repeated with similar sections many times to the left until section 4 is built. Modular section 1 is connected with modular section 4 with the use of pallet cross piece 600. The pallet cross-piece can also be made with thicker wall sections to increase the rigidity of the cross section and provide a more rigid pallet. Similarly, a dual connector middle piece 300 is used to connect section 4 with section 5, as illustrated in FIG. 1. Sections 4 and 5 are connected with the tubular ends of the modular section. The dual connector piece is also used to connect sections 1 to 2, sections 2 to 3, and sections 5 to 6. The modular design of the tubular sections allows for the continuous structure to be divided into several regions for ease of repair or serviceability.

[0019] The modular sections are connected together with the snap fit assembly to form the overall structure shown as an example in FIG. 1.

[0020] The modular sections can comprise two or more sections that snap in to one or several units. As an example, the pallet structure in FIG. 1 depicts 6 modular sections and cross pieces that are further illustrated in Section A-A (FIG. 4) and Section B-B (FIG. 5). Section A-A illustrates the use of the design for the thermoplastic material, though it also sufficiently describes the design for metallic, plastic, composite, or other polymer materials. Alternate versions of the invention include other designs with tabs that interlock, other manufacturing processes for polymer materials, and other polymer-based, organic-based, and metallic-based materials. Variations on the design include manners to snap-fit pieces of tubular sections to form a modular structure. This can include other flange designs on the end of the cross section and the mating tubular or solid sections. Additionally, the interlocking tubular sections of the top walls can be secured by adhesive, welding, bonding agent, or mechanical fasteners so that the resulting joint is of permanent and the pallet sections form an integral pallet unit. Also, the pallet section joint may be heat or chemically fused during assembly to prevent inadvertent separation of the pallet sections during use.

[0021] If a section becomes damaged, it can be replaced and then reassembled with a new section for the structure. The repair and reassembly can occur at the end user's location. This should reduce the cost of repair and shipping. In other words, my invention is modular and as such can be repaired in a snap fit assembly and disassembly fashion as the end user's location. Similarly, a composite lumber deck produced from the tubular sections would be significantly lighter and easier to repair than the current solid plastic lumber deck. 

I claim:
 1. A method for manufacture of tubular pallet, comprising: (a) forming a plurality of tubular pallet sections each being of generally cross-sectional configuration and having spaced upper and lower walls and spaced side walls, at least two of said upper and lower walls of each of said tubular interlocking sections being top and bottom walls defining the flange of one section intersecting the groove of the neighboring section extending the length of the respective top and bottom wall; and (b) establishing interlocking assembly of said interlocking sections for securing top and bottom walls of said plurality of pallet sections in interlocked assembly.
 2. The method of claim 1, further comprising, during forming, establishing a pair of spaced generally parallel top and bottom walls interconnected by top and bottom walls and forming said interlocking sections being located on said top walls, bottom walls, or both top and bottom walls.
 3. The method of claim 1, further comprising, after establishing interlocking assembly of said interlocking sections, securing said interlocking sections in permanent and immovable assembly.
 4. The method of claim 3, further comprising, adhesive bonding of said interlocking sections.
 5. The method of claim 3, further comprising, thermal welding of said interlocking sections.
 6. The method of claim 3, further comprising, mechanically fastening of said interlocking sections.
 7. A pallet, comprising: (a) a plurality of tubular interlocking pallet sections each being of generally cross-sectional configuration and having spaced upper and lower walls and spaced side walls, at least two of said upper and lower walls of each of said tubular interlocking sections being top and bottom walls defining the flange of one section intersecting the groove of the neighboring section extending the length of the respective top and bottom wall; (b) at least two tubular elements are located next to one another with collinear edges and are oriented in the same direction to support loads on top and bottom surfaces and resist bending; and (c) at least one cross-member tubular section with flanges on the top and bottom walls of the right and left sides.
 8. The pallet of claim 7, further comprising: (a) said interlocking sections being a protruding flange and corresponding channel groove defined by adjacent pallet sections; (b) said interlocking sections being disposed in mechanically interlocked assembly; (c) said interlocking sections being disposed in adhesive bonding interlocked assembly; and (d) said interlocking sections being disposed in heat welded interlocked assembly.
 9. The pallet of claim 7, further comprising: (a) each of said pallet sections defining a planar top and bottom walls and said spaced side walls having substantially parallel relation and being oriented in substantially perpendicular with said planar top and bottom walls; (b) said top and bottom walls of adjacent pallet sections defining said interlocking elements; and (c) said interlocking elements securing top and bottom walls of adjacent pallet sections in interlocked assembly and orienting said planar top walls of said pallet sections in substantially co-planar relation.
 10. The pallet of claim 9, further comprising: (a) each of said tubular pallet sections being of integral construction and said top and bottom walls being of planar configuration and being disposed in substantially parallel relation, said spaced walls being disposed in substantially parallel relation and being oriented in substantially perpendicular relation with said planar top wall and said planar bottom wall; (b) said top and bottom walls of adjacent pallet sections defining said interlocking elements; and (c) said interlocking sections securing top and bottom walls of adjacent pallet section in interlocked assembly and orienting said planar top walls of each of said pallet sections in substantially co-planar relation and orienting said planar bottom walls of each said pallet sections in substantially co-planar relation. 